Abstract: An automated sphygmomanometer which models the oscillometric envelope as two lines through the points defined by pressure and amplitude which are determined during the oscillometric blood pressure determination. One of the lines is the best fit through the points on the low pressure (diastolic) side of the oscillometric envelope, while the other line is the best fit through the points on the high pressure (systolic) side of the oscillometric envelope. The dividing point for the low and high pressure sides is chosen as the point where the best fit line through the points on one side and the best fit line through the points on the other side have the greatest amplitude at the point of intersection. The result is a linear approximation of the oscillometric envelope by two lines forming a triangle with the baseline. A second pass is preferably performed to improve the linear approximation by eliminating points with oscillation amplitudes that are outside of the area of interest.

Abstract: An automated sphygmomanometer in which the timeout duration of respective deflation periods during which oscillatory complexes may be detected is alternated so that the monitor cannot synchronize with the heart rate for more than one deflation step. The timeout durations at each deflation step are alternated to have long-short-long-short durations so that the overall duration of the measurement cycle is preferably about the same as in conventional monitors in which the timeout periods all have the same duration. Once the oscillatory complexes are detected, the timeout is typically not needed and the processing proceeds to the next deflation step in a conventional manner.

Abstract: A patient monitoring system includes a pulse oximeter sensor and an audible alarm which is not produced when a blood pressure module is taking measurements, but only during that portion of the cycle that affects the pulse oximeter reading. During such measurements, the pulses detected by the oximeter decrease below a threshold T.sub.oxim. An audible alarm is caused to receive a logic level of zero by an AND gate through the detection of measurements exceeding a minimum pressure P.sub.min on the blood pressure module. The audible alarm continues to receive such a logic level until the measurements exceed a threshold P.sub.thr. After that time, the audible alarm AND gate logic level is reset to one, so as to permit reporting of pulses missing at the oximeter. None of the other alarms, such as the actual SPO.sub.2 reading, are affected by the AND gate. Accordingly, the present invention does not affect the taking of important SpO.sub.

Abstract: A patient monitoring system includes a pulse oximeter sensor and an audible alarm which is not produced when a blood pressure module is taking measurements, but only during that portion of the cycle that affects the pulse oximeter reading. During such measurements, the pulses detected by the oximeter decrease below a threshold T.sub.oxim. An audible alarm is caused to receive a logic level of zero by an AND gate through the detection of measurements exceeding a minimum pressure P.sub.min on the blood pressure module. The audible alarm continues to receive such a logic level until the measurements exceed a threshold P.sub.thr. After that time, the audible alarm AND gate logic level is reset to one, so as to permit reporting of pulses missing at the oximeter. None of the other alarms, such as the actual SpO.sub.2 reading, are affected by the AND gate. Accordingly, the present invention does not affect the taking of important SpO.sub.

Abstract: A blood pressure cuff is applied about a subject's artery, and inflated above the systolic level thus fully occluding the artery for a full heart cycle. The cuff pressure is thereafter reduced to permit an increasing flow through the progressively less occluded artery, and a measure of the peak amplitudes of the successively encountered blood pressure (oscillatory complex) pulses stored in memory. Also retained is the cuff pressure obtaining for each stored complex peak. In accordance with varying aspects of the present invention, the stored complex peak-representing data ensemble is corrected for aberrations; and improved data processing operates on the stored (and advantageously corrected) pulse peak data and the corresponding cuff pressure information to determine the subject's systolic arterial blood pressure.

Abstract: The deflation of the inflatable and deflatable cuff worn by a subject during automatic sphygmomanometric measurement is accomplished in unequal size decrements and principally in larger steps than 7 Torr. Each step after detection of the initial oscillations is determined in the first instance by reference to a look-up table or an equation as a function of prevailing cuff pressure. This Base Step dimension is augmented by a factor proportional to the last oscillation amplitude, the factor being increased after detection of the maximum oscillation amplitude. A valve mechanism with at least two different effective orifice sizes is used for deflation, the smaller size effective orifice being used first, to maintain control over the decrement step rate while holding the time for decrement within a predetermined limit of 8 mSec. per Torr, i.e., maintaining the rate above 125 Torr per second.

Abstract: A pulse oximetry system is provided in which LEDs of two different wavelengths illuminate tissue containing arterial blood flow. A photodiode receives light from the LEDs and produces electrical signals containing pulsatile components. The components of the two wavelengths are separated and the pulsatile waveforms are monitored until signal peaks are detected at the end of diastole. The waveforms are then integrated over the systolic interval, and the integrals are combined with the signal peak values to determine an index value. The index value is used to select a value representative of oxygen saturation from a look-up table.

Abstract: A blood pressure cuff is applied about a subject's artery, and inflated above the systolic level thus fully occluding the artery for a full heart cycle. The cuff pressure is thereafter reduced to permit an increasing flow through the progressively less occluded artery, and a measure of the peak amplitudes of the successively encountered blood flow (oscillatory complex) pulses stored in memory. Also retained is the cuff pressure obtaining for each stored complex peak. In accordance with varying aspects of the present invention, the stored complex peak-representing data ensemble is corrected for aberrations; and improved data processing operates on the stored (and advantageously corrected) pulse peak data and the corresponding cuff pressure information to determine the subject's mean arterial blood pressure.

Abstract: A blood pressure cuff is applied about a subject's artery, and inflated above the systolic level thus fully occluding the artery for a full heart cycle. The cuff pressure is thereafter reduced to permit an increasing flow through the progressively less occluded artery, and a measure of the peak amplitudes of the successively encountered blood flow (oscillatory complex) pulses stored in memory. Also retained is the cuff pressure obtaining for each stored complex peak. In accordance with varying aspects of the present invention, the stored complex peak-representing data ensemble is corrected for aberrations; and improved data processing operates on the stored (and advantageously corrected) pulse peak data and the corresponding cuff pressure information to determine the subject's diastolic arterial blood pressure.

Abstract: An inflatable, deflatable cuff, worn by the subject, is coupled to an air reservoir which is at a predetermined pressure which is above systolic pressure. The pressure head is established by a pump mechanism preferably located within the reservoir. When the reservoir is operatively coupled to the cuff, the cuff quickly inflates to a desired artery-occluding initial pressure preparatory to a following blood pressure measuring cycle of operation. The air pump resumes air flow into the reservoir when pressure within the reservoir falls below a predetermined threshold in preparation for a subsequent measurement cycle. The pump also supplies air directly to the cuff should the reservoir contents ever be inadequate to inflate fully the occluding cuff.

Abstract: A blood pressure cuff is applied to the patient, pumped to a pressure above systolic, and then is reduced in pressure decrements. At each decrement, complexes are detected by investigating the signal slope, and peaks of the complexes are measured and compared. During the complex detection process, the signal slope is measured periodically at a rapid rate, and unless the slope meets predetermined criteria, the input filters are clamped to a baseline, and the process is repeated.

Abstract: A pressure cuff on the patient is inflated to a predetermined pressure above systolic, and then is deflated incrementally. At each decrement, oscillatory complexes are detected, and respective peaks are compared and evaluated as "true" complexes if they are within certain size matching criteria. After such "true" complexes are identified at a predetermined number of levels (e.g. 2 or 3), only a single complex is investigated at subsequent levels, provided specified size and timing criteria are met.

Abstract: A device for simulating the pressure readings obtained from the arm of a living subject whose blood pressure levels are being determined by an oscillometric blood pressure monitor, includes a pulse pressure chamber for generating pressure pulses at a rate equivalent to a preselected pulse rate. The input to the pressure chamber is attached to the pressure cuff of the monitor and the output is connected to the pressure transducer of the monitor. In order to balance the pressure across the chamber and to apply the full cuff pressure to the monitor transducer, a normally-open valve is connected across the pressure chamber. This valve, however, is closed when the chamber creates a pressure pulse so that the pulse is added to the applied cuff pressure at the monitor transducer. A processor generates electrical signals that control the amplitude of the pressure pulses created by the chamber, depending on preselected values for simulated systolic, mean arterial and diastolic pressures.

Abstract: An adaptive monitor and method for rapidly determining blood pressure, selects an initial cuff pressure to be applied to an artery of the test subject and then measures the amplitude of pressure pulses caused by the pumping of blood by the subject's heart. The cuff pressure is incrementally increased while the pulse amplitudes are monitored in order to obtain blood pressure readings by the oscillometric method. If the pulse amplitudes decrease for increases in pressure above the initial value, it is taken as an indication that mean arterial pressure is below the initial cuff pressure. Thus the cuff pressure is substantially decreased to a new initial value and the process is restarted.